Effect of salinomycin and enzyme supplementation on nutrient digestibility and the performance of pigs fed barley- or rye-based diets

Abstract

Two experiments of a factorial design (sex × treatment) were conducted to determine the effects of enzyme and salinomycin supplementation on the nutritive value of barley or rye-based diets for growing pigs fed from approximately 20 to 85 kg. For exp. 1, 72 crossbred pigs were fed either a barley-based control diet or a similar diet supplemented with enzyme (Aspergillus niger; 750 units g −1 beta-glucanase and 650 units g −1 pentosanase), salinomycin (25 ppm) or both additives in combination. For exp. 2, two replicates of 48 pigs were fed either a barley-based diet, an unsupplemented rye-based diet or a rye-based diet supplemented with enzyme, salinomycin or both additives. During both experiments, chromic oxide (0.5%) was added to the diet of four to six pigs/treatment to act as a digestibility indicator starting when the pigs reached 42 kg. Neither enzyme nor salinomycin, alone or in combination, significantly improved the growth rate or feed efficiency of pigs fed barley or rye. Supplementation of barley with the combination of additives significantly (P < 0.05) improved protein digestibility while neither enzyme nor salinomycin had any effect on nutrient digestibility when fed alone. In rye-based diets, salinomycin, both alone and in combination, significantly (P < 0.05) improved the digestibility of crude protein and energy. Dry matter digestibility of the rye-based diets was unaffected by treatment. Key words: Swine, rye, barley, beta-glucanase, pentosanase, salinomycin